1. Technical Field
The present invention relates in general to a vehicle speed detection system and, in particular, to a method, system and program for auditing driver compliance to a current speed limit range. Still more particularly, the present invention relates to a method, system and program for determining whether the vehicle""s actual speed is within a current position-dependent speed limit range without the use of local speed transmitters.
2. Description of the Related Art
Speed limits and driving conditions along any given route may change frequently, particularly in urban settings. In addition, along a given route speed limits may change according to the time of day, such as during school hours or rush hours.
The current and accepted method of informing the driver of the speed limit is through posted speed limit signs on the side of the road. However, it is easy for drivers to become distracted and not notice changes in speed limit sign postings. In addition, drivers may intentionally or unintentionally exceed the posted speed limit. Exceeding a posted speed limit can have negative consequences such as personal injury, property damage, and fines from speeding tickets. Moreover, when multiple speed limit signs are posted for a single section of road (e.g. a day speed limit and a night speed limit), a driver must determine which speed is applicable.
In order to aid drivers with information about changing speed limits, several systems in addition to posted speed limit signs have been developed. For example, U.S. Pat. No. 6,008,740 (""740) describes a system for placing local transmitters near roadsides that are set to broadcast the speed limit for that range of road within a particular range and frequency. According to ""740, vehicles equipped with receivers tuned to the broadcast frequency can detect speed limit broadcasts when within the broadcast range in order to provide an on-board alert to drivers exceeding the broadcast speed limit.
However, while ""740 does provide an alternate system to posting speed limit signs, ""740 requires placing a locally broadcasting transmitter for each speed limit designation along a roadway and in each vehicle utilizing the system. The cost of implementing such a system of multiple local transmitters is undesirable in that it would be costly to place as many local transmitters as would be needed for the system to be effective.
For example, consider an urban area with a dense network of roads, each with unique speed limits. A speed limit system would have to correctly identify current street locations and speed limits, and not be confused with an adjacent street with a potentially different speed limit. This differentiation would be difficult for a system using radio transmission. Inconsistencies in broadcast range would most likely require a tight web of low power transmitters. Purchase and maintenance costs for this type of system with a large number of units would typically be prohibitive.
Therefore, in view of the foregoing, it would be desirable to provide a method, system and program for alerting a driver of current speed limits which does not require an excessive number of transmitters and which would not present transmission difficulties in areas with multiple speed limits in a small range. In particular, it would be advantageous to provide such a centralized database of position-dependent speed limits wherein designations according to type of car, time of day, weather conditions, etc. are included.
It is therefore an object of the present invention to provide a vehicle speed detection system.
It is another object of the present invention to provide a method, system, and program for auditing driver compliance to current speed limits.
It is yet another object of the present invention to provide a method, system and program for determining whether the vehicle""s actual speed is within a current position-dependent speed limit range without the use of local speed transmitters.
In accordance with the present invention, a position of a vehicle is detected by a receiver at the vehicle from a global positioning system. A speed limit associated with the position is determined from a centralized database accessible via a wireless network. An actual speed of the vehicle at the detected position is compared with the determined speed limit for the detected position, such that if it is determined that the actual speed exceeds the determined speed limit at the detected position, the driver may be alerted.
All objects, features, and advantages of the present invention will become apparent in the following detailed written description.